Balancing means for hot-cathode rectifiers



Dec. 18, 1928.

A. L. ATHERTON BALANCING MEANS FOR HOT CATHODE RECTIFIERS Filed Nov. 20. 1920 /3 l0 /4 8 5 5 M T Ai'TORNEY Patented Dec. "18, 1928.

UNITED STATES PATENT OFFICE.

ALFRED L. ATHERTON, or PITTSBURGH, PENNSYLVANIA, AssIeNoR To wnsrmenoose nnnc'rnrc a MANUFACTURING COMPANY, A CORPORATION or PENNSYL- VANIA.

:BALANomo MEANS FOR EOT-CATHODE 'nncrrrrnas.

Application filed November 20,1920. Serial No. 425,486.

My invention relates to hot-cathode-rectifier systems and particularly to those systems employing a plurality of bulbs.

Full-wave, hot-cathode rectlfiers are liable to cause noise if used on telephone batteries, the noise being due, at least in part, to d fferences in the bulbs. Difi'erences 1n purity of gas, percentage of gas, filament temperatures, spacebetween anode and filament and filament area will make differences 1n the bulbotential-drops or are voltages across the bulbs, which result in noisy lines.

Variations in bulb-potential-drop may be effected by adjustment of the filament excitap tion, and I propose to use this means for neutralizing the variations in bulb-potentialdrop which are dueto other causes.

The single figure of the accompanying drawing is a diagrammatic view of apparatus and circuits embodying my lnventlon. As here illustrated, my invention may consist of a pair of bulbs 1 and 2, each having an anode 3 and a filamentary cathode 4. Power is supplied from any suitable alternatingcurrent source, such as the transformer windings 5, having a mid-point 6 which is connected to one terminal of the direct-current load, indicated as a battery 7, the other terminal of the direct-current load being connected to the filament circuits.

The filaments are excited by means of a pair of auxiliary transformer coils 8. 'The coils 8 are connected in series, with their outer terminals connected, respectively, to corresponding terminals of the filaments 4. The other terminals of filaments 4 are connected together through an impedance means 9. A sliding contact member 10 cooperates with the impedance means 9 and is connected to the common terminal of the coils 8, 8. The impedance means 9 may be a carbon pile or other resistance or it may be a reactance coil in the form of an auto-transformer, or any other suitable device.

With this arrangement, it is possible to compensate for initial variations in the bulbotentiaLdrops, and also for chan es in the Bulb conditions after a long perio of service, by adjustin the respective filament temperatures. Su adjustments may be made satisfactorily by hand, since bulb conditions do not vary rapidly.

However, in case the requisite attendance is undesirable, automatic operation may be employed, as indicated schematically in. the drawing, such means being shown as comprising coils 11 and 12, placed in series with the respective anode leads of the bulbs, and having armatures 13, 14 which are connected together by a rod 16 carrying the variable sliding contact member 10. The coils 11 and 12 are so arranged'that an increase in current in either bulb circuit actuates the rod 16 and causes the sliding contact member 10 to decrease the filament-excitation current of said bulb.

It is to be understood, of course, that the automatic means shown is merely suggestive, as the details of such means do not constitute any part of my invention and any suitable I automatic means may be used.

I have shown my invention as a plied to a single-phase circuit having two iulbs, one bulb rectifying each half wave of the alternating current. The compensating means which I have described is useful in maintaining the currents or voltages in successive half waves equal in value, thus obviating a particularly troublesome cause of noise in a telephone circuit 15 which may be connected to the battery 7. I

It is obvious, however, thatmy invention is not limited to telephone systems, but is ap plicable to a single rectifier or to a plurality of rectifiers arranged in parallel or arranged in a polyphasecircuit. In fact, my filamentcontrol means may be used to vary the load current of a rectifier bulb in any power circuit. It will be understood, therefore, that my claims will be construed to cover all modifications or equivalents which could be supplied by those skilled in the art.

I claim as my invention 1. The combination with an A. C. source, a

plurality of hot-cathode half-wave rectifiers 9 2. The combination with a rectifier system comprising a pluralit of filamentary bulbs supplying a common oad, of means responsive to the respective anode currents of said bulbs for maintaining the currents in the several bulbs e ual.

3. In a rectilying system, the combination with an A. C. source and a plurality of halfwave hot-cathode. rectifiers each providing a space-current path from a line terminal of said source to a common load, a connection of the other terminal of said load to the neutral of said source, and automatic means for compensating for differences in potential-drops of the several rectifiers.

4. The combination with an alternatingcurrent system and a direct-current system, of a pair of space-current devices operating in parallel across said direct-current system and operating on opposite half-waves of said alternating current system, means for adjusting the impedance of said devices, and means responsive to operating conditions in said devices for maintaining a predetermined relation between the impedances of the same.

5. The combination with a direct-current load, an alternating-current source, and a pair of rectifiers connected in parallel between said alternating-current source and said direct-current load to rectify opposite half waves of the alternating current, of means responsive to the difference in operating conditions in the two rectifiers for maintaining a predetermined relation in the opera tion of the two rectifiers.

6. The combination with a direct current load, an alternating-current source, and a pair of rectifiers connected in parallel between said alternating-current source and said direct-current load to rectify opposite half waves of the alternating current, each of said rectifiers comprising a filamentary cathode, of means for exciting said filamentary cathodes, and means responsive to the difference in operating conditions in said two rectifiers for adjusting the relative degree of excitation of said two cathodes.

7. The combination with a direct-current load, a plurality of alternating-current sources, and a plurality of rectifiers connected in parallel between said direct-current load and said alternating-current sources, of means rosponsive to the operating conditions in said rectifiers for maintaining a predetermined relation between the impedances of the circuits of the several rectifiers.

8. In a space-current tube system, the combination with a plurality of space-current devices having separate hot cathodes, of energizing means for supplying heating current to said cathodes, and adjustable current controlling means connecting said energizing means to said cathodes, said controlling means being so arranged that an adjustment produc ing an increase of heating current in one device produces a decrease in the heating current in a second device.

9. In a space-current tube system, the combination with a pair of space-current devices having separate hot cathodes, of means for connecting said cathodes in series, and ad- 'ustable controlling means for supplyin the eating current for said cathode throu the series connection between the same sai controlling means being so arranged that an adjustment of the controlling means to produce a current increase in one cathode simultaneously roduces a current decrease in the other cat ode, and vice versa.

10. In a space-current tube system, the combination with two filamentary cathodes, of a source of electrical ener having two end terminals and aninterme 'ate terminal, said cathodes being connected in series between said end terminals, and a conducting connection between said intermediate terminal and a point intermediate said cathodes.

11. In a space-current tube syste the combination with two serially connec filamentary cathodes, of a source of electrical energy having two end terminals connected in series with said two cathodes, said source having an intermediate adjustable terminal connection to an impedance intermediate said cathodes to control the current through the same, said adjustable terminal connection being so arranged that an adjustment producing a current increase in one cathode simultaneously produces a current decrease in the other cathode, and vice versa.

12. In a space-current tube system, the com bination with two filamentar cathodes, of a source of electrical energy li aving two end terminals and an intermediate terminal, an impedance device connected between said two 105 cathodes, the free terminals of said cathodes being connected to the end-terminals of said source, and a connection between said intermediate terminal and said impedance device.

13. In a space-current tube system, the comno bination with two filamentary cathodes, a source of electrical energy having two end terminals and an intermediate terminal, an impedance device connected between said two cathodes, the free terminals of said cathodes 115 being connected to the end-terminals of said source, and means for connecting said intermediate terminal to various points on said impedance device to differentially control the current flowing through said cathodes.

14. In. combination with a direct-current load, an alternating-current source, a pair of hot-cathode diode tubes connecting the respective line terminals of said source to the input terminal of said load, a connection from 125 the other terminal of said load to the neutral of said source, and means responsive to difierences in the load currents of said rectifiers to decrease the temperature of the cathode of the rectifier taking the larger load current.

15. In combination with a direct-current the load currents of said rectifiers to increase load, an alternating-current source, a pair of the temperature of the cathode of the rectifier hot-cathode diode tubes connecting the line taking the smaller load current. 10 terminals of said source to the input terminal In testimony whereof, I have hereunto sub- 6 of said load, a connection from the other terscribed my name this 12th day of November minal of said load to the neutral of said 1920. source, and means responsive to difl'erences in ALFRED L. ATHERTON. 

